I have several center fed, half wave sloping dipoles for 80 and 40..
I'm debating on putting up several 80 meter OWAs, or just making the the
Fans for 80 and 40. On 40, I can get away with RG8X at the legal limit,
but not on 75/80.
However I only operate below 3.7 and 7.200.The SWR remains relatively
low, below 7.2 and easily compensated for with the AT5K-HP and the 8X
handles it nicely. With 80, 3.7 to 3.5 is a different story, but the
tuner still handles it nicely. OTOH the voltage might be a tad high for
8X with the high SWR. Still, using LMR 400, or the heavier BuryFlex(TM)
will work and I "think" I can get enough turns through 7 cores, with the
coax bundled instead of equally spaced turns around the cores, to tame
the common mode RF. If not, I can add a second choke as I have now.
I'm leaning toward the fan instead of the OWA as I can get 5 slopers as
in the antenna book for switchable directivity with a f/b ratio? The
ones to the NE and SE would be hidden by the trees. Hopefully I can get
the desired results with a single choke at each feed point. That's a
whopping 35 cores. A second 5 core takes it up to 60 cores as well as
adding up to a lot of coax! For the 7 turn at roughly 21 feet the 5
chokes add up to about 105 feet and about 80 feet (I've not calculated
that yet) is another 400 feet. I probably shouldn't have given so much
used LMR400 away. I might still have 400 or 500 feet left. I do have a
new, 500 ft roll of BuryFlex, but I need a 100 feet of BuryFlex to get
from the AV640 under the sod to the tower grounding plate and then to
the 6-pack.
Has anyone modeled one of these setups just using dipoles on any band?.
--
73
Roger (K8RI)
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